Radio-frequency device and wireless communication device for enhancing antenna isolation

Abstract

A radio-frequency device includes a grounding element, a first antenna including a first parasitic element, a second antenna, a third antenna and a second parasitic element, wherein the grounding element is shared by the first, second and third antennas, the second parasitic element is electrically connected to the grounding element for guiding a first reflected signal from the first antenna to the second parasitic element, and the first parasitic element is electrically connected to the grounding element for guiding a second and third reflected signals from the second and third antennas to the first parasitic element, so as to enhance isolations of the first, second and third antennas.

What is claimed is: 
     
       1. A radio-frequency device for a wireless communication device, comprising:
 an antenna disposition area; 
 a grounding element, for providing ground; 
 a first antenna, disposed in the antenna disposition area for transmitting or receiving a first radio signal, wherein the first antenna comprises:
 a metal coupling piece; 
 a first radiating element, electrically connected to the ground and extended directly from the grounding element for emitting the first radio signal; 
 a first signal feed-in element, electrically connected to the metal coupling piece for coupling the first radio signal to the first radiating element via the metal coupling piece such that the first radio signal is emitted via the first radiating element; and 
 a first parasitic element, electrically connected to the grounding element; 
 
 a second antenna, disposed in the antenna disposition area for transmitting or receiving a second radio signal; 
 a third antenna, disposed in the antenna disposition area for transmitting or receiving a third radio signal; and 
 a second parasitic element, disposed in the antenna disposition area and electrically connected to the grounding element for guiding a first reflected signal generated from the first radio signal to the second parasitic element so as to enhance isolations of the first antenna, the second antenna and the third antenna; 
 wherein the grounding element is disposed between the first antenna and the second parasitic element, the first antenna and the second antenna, and the first antenna and the third antenna, the grounding element is shared by the first antenna, the second antenna and the third antenna, each of the first radiating element, the first parasitic element, and the second parasitic element is formed as an extended portion of the grounding element, the metal coupling piece is disposed between the first parasitic element and the first radiating element, and the first parasitic element is used for guiding a second reflected signal generated from the second radio signal and a third reflected signal generated from the third radio signal to the first parasitic element so as to enhance isolations of the first antenna, the second antenna and the third antenna. 
 
     
     
       2. The radio-frequency device of  claim 1 , wherein the grounding element is formed with a first slot, the first slot is disposed between the first signal feed-in element and the first radiating element such that a current in the first radio signal flows to the first radiating element from the first signal feed-in element around the first slot. 
     
     
       3. The radio-frequency device of  claim 1 , wherein the second antenna comprises:
 a second radiating element; 
 a third radiating element, electrically connected to the grounding element; 
 a second signal feed-in element, electrically connected to the second radiating element for transmitting the second radio signal to the second radiating element such that the second radio signal is emitted via the second radiating element; and 
 a first short-circuit unit, electrically connected between the second radiating element, the grounding element and the second parasitic element. 
 
     
     
       4. The radio-frequency device of  claim 1 , wherein the third antenna comprises:
 a fourth radiating element; 
 a fifth radiating element, electrically connected to the grounding element; 
 a third signal feed-in element, electrically connected to the fourth radiating element for transmitting the third radio signal to the fourth radiating element such that the third radio signal is emitted via the fourth radiating element; and 
 a second short-circuit unit, electrically connected between the fourth radiating element, the grounding element and the second parasitic element. 
 
     
     
       5. The radio-frequency device of  claim 1 , wherein a radio signal processing unit of the wireless communication device is disposed between the first antenna, the second antenna, the third antenna and the second parasitic element in the antenna disposition area. 
     
     
       6. The radio-frequency device of  claim 1 , wherein a first length of the first parasitic element is substantially equal to a quarter-wavelength corresponding to a frequency band of the first radio signal, the second parasitic element is disposed between the first antenna and the second antenna, a second length of the second parasitic element is substantially equal to a quarter-wavelength corresponding to the frequency band of the first radio signal, and a third length of the first radiating element is substantially equal to a quarter-wavelength corresponding to the frequency band of the first radio signal. 
     
     
       7. The radio-frequency device of  claim 1 , wherein the second parasitic element comprises a branch, disposed at an end of the second radiating element for coupling the second radiating element to make signal connections between the second parasitic element and the second radiating element, wherein the second radiating element substantially extends along a first direction, the fourth radiating element substantially extends along a second direction, and the first direction is perpendicular to the second direction. 
     
     
       8. The radio-frequency device of  claim 1 , wherein the second antenna comprises:
 the second parasitic element, for emitting the second radio signal; 
 a second radiating element, electrically connected to the grounding element; 
 a second signal feed-in element, electrically connected to the second radiating element for coupling the second radio signal to the second parasitic element via the second radiating element such that the second radio signal is emitted via the second parasitic element; and 
 a first short-circuit unit, electrically connected to the second radiating element and the grounding element. 
 
     
     
       9. The radio-frequency device of  claim 8 , wherein the grounding element is formed with a second slot, wherein the second slot is disposed between the second antenna and the third antenna. 
     
     
       10. A wireless communication system, comprising:
 a system grounding element, for providing ground; 
 a radio signal processing unit, for processing a plurality of radio signals; and 
 a radio-frequency device, comprising:
 an antenna disposition area; 
 a grounding element, for providing ground; 
 a first antenna, disposed in the antenna disposition area for transmitting or receiving a first radio signal of the plurality of radio signals, wherein the first antenna comprises:
 a metal coupling piece; 
 a first radiating element, electrically connected to the ground and extended directly from the grounding element for emitting the first radio signal; 
 a first signal feed-in element, electrically connected to the metal coupling piece for transmitting the first radio signal to the first radiating element via the metal coupling piece such that the first radio signal is emitted via the first radiating element; and 
 a first parasitic element, electrically connected to the grounding element; 
 
 a second antenna, disposed in the antenna disposition area for transmitting or receiving a second radio signal of the plurality of radio signals; 
 a third antenna, disposed in the antenna disposition area for transmitting or receiving a third radio signal of the plurality of radio signals; and 
 a second parasitic element, disposed in the antenna disposition area and electrically connected to the grounding element for guiding a first reflected signal generated from the first radio signal to the second parasitic element so as to enhance isolations of the first antenna, the second antenna and the third antenna; 
 wherein the grounding element is disposed between the first antenna and the second parasitic element, the first antenna and the second antenna, and the first antenna and the third antenna, the grounding element is shared by the first antenna, the second antenna and the third antenna, each of the first radiating element, the first parasitic element, and the second parasitic element is formed as an extended portion of the grounding element, the metal coupling piece is disposed between the first parasitic element and the first radiating element, and the first parasitic element is used for guiding a second reflected signal generated from the second radio signal and a third reflected signal generated from the third radio signal to the first parasitic element so as to enhance isolations of the first antenna, the second antenna and the third antenna. 
 
 
     
     
       11. The wireless communication device of  claim 10 , wherein the grounding element is formed with a first slot, the first slot is disposed between the first signal feed-in element and the first radiating element such that a current in the first radio signal flows to the first radiating element from the first signal feed-in element around the first slot. 
     
     
       12. The wireless communication device of  claim 10 , wherein the second antenna comprises:
 a second radiating element; 
 a third radiating element, electrically connected to the grounding element; 
 a second signal feed-in element, electrically connected to the second radiating element for transmitting the second radio signal to the second radiating element such that the second radio signal is emitted via the second radiating element; and 
 a first short-circuit unit, electrically connected between the second radiating element, the grounding element and the second parasitic element. 
 
     
     
       13. The wireless communication device of  claim 10 , wherein the third antenna comprises:
 a fourth radiating element; 
 a fifth radiating element, electrically connected to the grounding element; 
 a third signal feed-in element, electrically connected to the fourth radiating element for transmitting the third radio signal to the fourth radiating element such that the third radio signal is emitted via the fourth radiating element; and 
 a second short-circuit unit, electrically connected between the fourth radiating element, the grounding element and the second parasitic element. 
 
     
     
       14. The wireless communication device of  claim 10 , wherein the radio signal processing unit is disposed between the first antenna, the second antenna, the third antenna and the second parasitic element in the antenna disposition area. 
     
     
       15. The wireless communication device of  claim 10 , wherein a first length of the first parasitic element is substantially equal to a quarter-wavelength corresponding to a frequency band of the first radio signal, the second parasitic element is disposed between the second antenna and the third antenna, a second length of the second parasitic element is substantially equal to a quarter-wavelength corresponding to the frequency band of the first radio signal, and a third length of the first radiating element is substantially equal to a quarter-wavelength corresponding to the frequency band of the first radio signal. 
     
     
       16. The wireless communication device of  claim 10 , wherein the second parasitic element comprises a branch, disposed at an end of the second radiating element for coupling the second radiating element to make signal connections between the second parasitic element and the second radiating element, wherein the second radiating element substantially extends along a first direction, the fourth radiating element substantially extends along a second direction, and the first direction is perpendicular to the second direction. 
     
     
       17. The radio-frequency device of  claim 10 , wherein the second antenna comprises:
 the second parasitic element, for emitting the second radio signal; 
 a second radiating element, electrically connected to the grounding element; 
 a second signal feed-in element, electrically connected to the second radiating element for coupling the second radio signal to the second parasitic element via the second radiating element such that the second radio signal is emitted via the second parasitic element; and 
 a first short-circuit unit, electrically connected to the second radiating element and the grounding element. 
 
     
     
       18. The wireless communication device of  claim 17 , wherein the grounding element is formed with a second slot, wherein the second slot is disposed between the second antenna and the third antenna.